‘Game of Thrones’ actors Rose Leslie and Kit Harington discuss tragic death on last night’s episode, “The Watchers on the Wall.”

Last night’s Game of Thrones was the most action-packed episode in the HBO fantasy series’ four-year history, as Mance Rayder’s wildling army finally made their strike against the highly outnumbered Night’s Watch. The battle was so epic that it took up the entirety of the episode, forcing viewers to...